Using an organic electroluminescent (EL) element, light can be emitted with high luminance at a low voltage, and various light colors can be obtained depending on types of organic compounds contained therein. In addition, a light emitting flat panel can be easily manufactured using the organic EL element. In recent years, the organic EL element has been highlighted as a light source of a light emitting module.
As illustrated in FIG. 21, there is known a light emitting module 100 including a rectangular flat light source unit 20 having such an organic EL element 10 as a light source and a socket 30 where the light source unit 20 is mounted detachably (for example, see Patent Literature 1). The socket 30 includes a rectangular hollow 40 where the light source unit 20 is fitted, and an engagement claw 50 provided in an inner circumference of the hollow 40 and elastically biased by a spring (not shown) inward of the light emitting module 100. The light source unit 20 has a holding portion 60 engaged with the engagement claw 50 in a position matching the engagement claw 50 on its side surface and is pivotably installed in the socket 30 with respect to a side facing that of the holding portion 60.
As the light source unit 20 is pivoted to the socket 30, the light source unit 20 abuts on the engagement claw 50 of the socket 30. As the light source unit 20 is further forced toward the socket 30 from this state, the engagement claw 50 slides toward the outside of the light emitting module 100 resisting to a biasing force of the spring, so that the light source unit 20 is fitted to the hollow 40. Then, the engagement claw 50 is elastically biased again toward the inside of the light emitting module 100 by the spring and is engaged with the holding portion 60 of the light source unit 20. In this way, the light source unit 20 is mounted to the socket 30.